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NANJING ALAS INTERNATIONAL CO., LTD
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Disc Blades: Mounted on a rotating cutter head. Common types: 4-6 blades, 8-12 blades, spiral blades. Best for: Large-diameter logs. Pros: Produces clean, high-quality chips. Main choice for paper mills.
Drum Blades: Fixed on a cylindrical cutter drum. Best for: Small to medium plants, complex raw materials (bark, small wood). Pros: Good adaptability to raw materials. Cons: Chip uniformity is worse than disc blades.
A8: Best toughness, strong impact resistance.
A8B: Upgraded A8. Better overall performance (toughness + wear resistance).
D2: Highest wear resistance and hardness, longest service life. Weakest toughness.
Type: High toughness cold work die steel
Hardness: HRC 58–62
Toughness: ★★★★★ (best)
Wear resistance: ★★★☆☆ (moderate)
High temp resistance: Good
Corrosion resistance: Average
Type: Optimized A8 steel
Hardness: HRC 58–62 (more stable)
Toughness: ★★★★☆ (better than A8)
Wear resistance: ★★★★☆ (better than A8)
High temp resistance: Excellent (not easy to anneal)
Corrosion resistance: Good
Type: High carbon high chromium cold work steel (semi-stainless steel)
Hardness: HRC 60–62
Toughness: ★★☆☆☆ (weakest)
Wear resistance: ★★★★★ (best)
High temp resistance: Average (easy to soften)
Corrosion resistance: Better than A8/A8B
Focus: High toughness and impact resistance. Low carbon content; alloy ratio (chromium, molybdenum, vanadium) emphasizes toughness.
Pros: Not easy to chip or break when cutting hardwood, knotty wood or wet wood. Suitable for high-impact, complex work.
Use: Small to medium chippers, branch shredders. Processes high-impact raw materials (logs, branches, mixed wood).
Focus: Optimized A8. Adjusts alloy composition and heat treatment to improve wear resistance and high-temp stability (keeps A8’s toughness).
Pros: Toughness is similar to A8; better wear resistance. No easy annealing during continuous high-temp work; sharp edge lasts longer. Excellent overall performance.
Use: Medium to large continuous production lines (papermaking, wood-based panels, pulping). Processes hardwood (rubber wood, eucalyptus).
Focus: High carbon high chromium (≈12% Cr) steel (semi-stainless steel). Known for extreme wear resistance, hardness and long service life.
Pros: Wear resistance is 2–3 times A8. Sharp edge lasts long; low replacement frequency. Better corrosion resistance than A8/A8B.
Cons: Poor toughness, high brittleness. Easy to crack under high impact; hard to process.
Use: Large, high-capacity continuous chippers. Processes high-wear, low-impact raw materials (softwood, bamboo, straw).
Superior Impact Resistance: A8 balances D2’s wear resistance and S7’s shock resistance.
Anti-Chipping: A8’s alloy is tougher than D2. It bends slightly instead of shattering under stress.
Full-Body Vacuum Heat Treatment: Hardness is uniform from edge to core. Creates a "self-sharpening" effect as the blade wears evenly.
Sharp A8 blades keep a sharp edge longer. This ensures:
Uniform chip size (good for pulp or biofuel).
Less energy use (sharp blades need less motor torque).
Low friction (mirror finish from precision CNC grinding reduces heat).
Mixed raw materials, high impact (hardwood, knotty wood, wet wood) → Choose A8 (prioritize toughness).
Continuous production, main raw material: hardwood → Choose A8B (best overall performance).
Softwood/bamboo/straw, high capacity → Choose D2 (best wear resistance, longest service life).
The core difference between the three chipper blade materials A8, A8B, and D2 lies in the different ratios of alloy elements such as carbon (C), chromium (Cr), molybdenum (Mo), and vanadium (V), which directly determine toughness, wear resistance, hardness, and cost. The following is a comparison of their standard chemical compositions (mass percentage, wt%) and key functions.
Element | A8 | A8B (A8 Modified) | D2 | Key Functions |
Carbon (C) | 0.50–0.60% | 0.55–0.65% | 1.40–1.60% | Determines basic hardness and wear resistance; the higher the content, the harder and more brittle |
Chromium (Cr) | 4.75–5.50% | 5.20–6.00% | 11.0–13.0% | Improves hardenability and corrosion resistance; forms hard carbides (e.g., Cr₇C₃) |
Molybdenum (Mo) | 1.15–1.65% | 1.40–1.80% | 0.70–1.20% | Refines grains, improves toughness and high-temperature stability; inhibits temper brittleness |
Vanadium (V) | 0.80–1.40% | 1.00–1.50% | 0.50–1.10% | Forms extremely hard VC carbides, significantly improves wear resistance; prevents grain growth |
Tungsten (W) | 1.00–1.50% | 1.20–1.70% | — | Improves hot hardness and high-temperature wear resistance |
Manganese (Mn) | 0.20–0.50% | 0.30–0.60% | 0.10–0.60% | Deoxidation, improves hardenability |
Silicon (Si) | 0.20–0.80% | 0.50–1.00% | 0.10–0.60% | Deoxidation, improves strength and oxidation resistance |
Phosphorus (P) | ≤0.030% | ≤0.025% | ≤0.030% | Harmful impurity, reduces toughness |
Sulfur (S) | ≤0.030% | ≤0.025% | ≤0.030% | Harmful impurity, reduces toughness |
Low C, medium Cr, high Mo/W: Carbon content is only 0.5–0.6%, ensuring matrix toughness; chromium is about 5% to provide basic wear resistance; molybdenum and tungsten work together to strengthen, achieving impact resistance and not easy to break.
Positioning: Priority to impact resistance, suitable for high-impact working conditions such as hardwood, knotty wood, and wet wood.
Fine-tuned on the basis of A8: C, Cr, Mo, V, and W are all slightly increased, greatly improving wear resistance and high-temperature stability while retaining the high toughness of A8.
Positioning: Optimal comprehensive performance and highest cost performance, suitable for medium and large-scale chippers with continuous production.
High C, ultra-high Cr, appropriate Mo/V: Carbon content is as high as 1.4–1.6%, forming a large number of hard carbides; chromium is about 12%, known as "semi-stainless steel", with top-level wear resistance and corrosion resistance.
Cost: The worst toughness and highest brittleness, easy to crack under high impact; high price and high processing difficulty.
Positioning: Priority to wear resistance and longest service life, suitable for raw materials with high wear and low impact such as softwood, bamboo, and straw.
Nanjing Alas International Co., Ltd. is a professional industrial tooling manufacturer focused on shear blades, bending dies, shredder blades, and custom wear parts. We offer full application engineering, material selection, setup guidance, and after-sales support to global customers.
Tell us your requirements, and our engineering team will provide professional solutions for blade specification, tool life optimization, and cost-effective production.